1. Field of the Invention
The present invention relates to the field of post anchors and, in particular, post anchors designed for use in connection with metal fence posts.
2. Description of the Related Art
A number of inventions have been patented that attempt to solve the problem of preventing a fence post from coming out of the ground. None of these inventions is as simple to install, easy to manufacture, and effective as the present invention. Some of these inventions cannot be used with contemporary metal fence posts, many of them require alteration of the fence post, and all of them consist of more than one part. The present invention, on the other hand, is designed specifically for use with modern metal fence posts, it does not require any alteration of the fence post, it provides resistance on both sides of the fence post, and it consists only of a single piece of material. For these reasons, it is superior to any of the previously patented inventions discussed below.
U.S. Pat. No. 1,169,821 (Hindmarsh, 1916) discloses a fence post constructed of sheet steel that is bent so that its general shape in cross-section is that of a V, and wherein each limb of the V is bent backward so as to form a vertical flange that lies parallel or nearly parallel with the limb of the V. According to the inventor, this shape would greatly stiffen the post so that it would resist the tendency to buckle under horizontal pressure. The lower end of the post is pointed, and barbs are located at the end of each limb of the V. Pivoting plates are optionally attached to the post to provide further resistance.
U.S. Pat. No. 1,717,557 (Halgrimson, 1928) provides a fence post anchor that mounts to the front of a steel post. The anchor device consists of four parts, namely, an attaching plate that is riveted to the post, a second plate that extends outward when the fence post is pulled upward, hinges or rings that secure the second plate to the attaching plate, and stop wings that limit the downward movement of the second plate. This particular anchor device provides resistance only on the front of the fence post.
U.S. Pat. No. 1,955,902 (Bullard, 1934) relates to an anchor device for a metal fence post. This device was designed to work with the older style of metal fence posts that do not have knobs on the front face of the post and would not likely work with today's fence posts. The device comprises a post, a tapered plate attached to the post, an abutment that extends angularly from the plate, an anchor plate that is pivotally connected to the tapered plate, and a lever. When upward force is applied to the lever, it causes an outward movement of the anchor plate, which provides the anchoring resistance.
U.S. Pat. No. 2,705,548 (Lionberger, 1955) describes another fence post anchor means. This device is designed to work with today's metal fence posts, but it requires alteration of the steel spade that is attached to the fence post. The anchor device comprises a pair of triangular movable plates that are mounted with hinges on each side of the existing spade on the front face of the fence post. These movable plates are curved downward at their tips.
Lionberger patented another fence post anchor device in U.S. Pat. No. 2,910,149 (Lionberger, 1959). This device was designed to work with modern metal fence posts, and it consists of one main flange with a pointed bite portion opposite a short side. The short side of the flange is attached to the fence post with hooks that loosely embrace the edges of the fence post. The flange also has a resilient tongue whose purpose is to accommodate the knobs or bosses that protrude from the front face of the fence post.
U.S. Pat. No. 4,663,902 (Abbott, Jr., 1987) discloses a fence post anchor that consists of a spade pivotally attached to a post and held in place by the use of a flexible strap. This particular device was designed for use with wood fence posts and is not adapted to work with modern metal fence posts.
U.S. Pat. No. 5,058,337 (O'Connor, 1991) provides a ground anchor that could be adapted for use with metal fence posts, although the patent itself does not explain how the device would attach to a metal fence post. Alteration of the fence post, or modification of the invention, would likely be required. The anchor device comprises a post, a plate of non-uniform thickness with bendable portions and a rigid portion, and a limit stop plate secured to the front face of the post.
U.S. Pat. No. 5,428,927 (Webb et al., 1995) discloses an anchor device that can be used with modern metal fence posts, but it requires alteration of the fence post for installation. The anchor device consists of an extending leg with an opening near the base end (in other words, a hole has to be drilled in the fence post), an elongated anchor with a longitudinal slot for receiving a portion of the post leg, and a pin that engages the anchor and passes through the leg opening.
In addition to the patents discussed above, which attempt to solve the problem of fence posts coming out of the ground, there are a number of patents that provide other types of anchoring devices. Although they are similar to the present invention in that their purpose is to keep something in the ground, none of these inventions possesses the simplicity of design and uniqueness of purpose of the present invention.
For example, the anchor device of U.S. Pat. No. 1,726,526 (Colvin, 1929) includes a shaft that drives the anchor device into the ground. The upper end of the shaft has an eye for the attachment of a guy line, and the lower end of the shaft has an eye through which a pivot pin is placed. Two flukes are pivotally mounted on the pin, and the shaft is surrounded by a conical enlargement that spreads the upper ends of the flukes when the guy line is pulled.
U.S. Pat. No. 1,774,288 (Nickerson, 1930) describes a rather complicated sign post anchor comprising a post, an anchor foot affixed to the post with side shoulders positioned laterally in relation to the post, a collar on the post above the side shoulders, and ground anchor arms that pivot on the collar and that engage the side shoulders when positioned horizontally. The collar is secured to the post with a pin and has cutaway portions that define spaced shoulders. The pins are positioned in relation to the spaced shoulders such that they limit rotational movement of the post and foot.
U.S. Pat. No. 1,807,488 (Michalicek, 1931) involves an anchoring device that is adapted for use in securing guy lines. The anchoring device includes a pair of arcuate sections that are transversely corrugated and that have at their upper edge an inturned flange that extends slightly downward toward the center of the device. Each arcuate section has two apertured ears, to which are connected links that are in turn pivotally connected to a floating plate at the bottom of the device. A rigid plate lies on top of the sections and has an opening through which a threaded rod is placed. The rod engages with an internally threaded boss and connects the anchor device to the object it is intended to secure. Rotation of the rod causes the two sections to be forced apart, which provides the anchoring resistance.
U.S. Pat. No. 2,334,989 (Brickman, 1943) discloses a metal highway guard support with two parallel flanges connected by a median web. The roadside flange connects to a resilient steel bracket that carries a plurality of cables to jointly form the guard rail element. A wing-like anchor plate is pivotally connected to the roadside flange through apertures in the flange. The anchor plate has a depending tongue that serves to stop the pivotal movement of the plate. The anchor plate is the same width as the roadside flange at its base but wider than the flange at its upper end.
U.S. Pat. No. 2,243,886 (Scott, 1941) provides an airplane mooring anchor that operates by means of an anchor rod that sits inside of a driving tube. When the driving tube is raised, it causes the two portions of the anchoring root element to spread apart. The driving tube is then removed and a mooring eye is threaded onto the upper end of the anchor rod.
U.S. Pat. No. 2,366,997 (Brand, 1945) involves a ground stake comprising a tubular shank, a pair of tapered flukes, and a pull cord. The pull cord is attached to the pivot of the flukes, directed over a pulley, and provided with a ring at its free end for attachment to a guy wire, tent rope, or other object that is to be anchored. U.S. Pat. No. 2,771,163 (Mafera, Jr., 1956) relates to a ground anchor that is comprised of a stake that is pointed at one end and that has at least one transverse slot. A fluke is placed into each transverse slot, and when the ground anchor is subjected to dislodging strains, the flukes move outward at right angles to the stake. Each stake wall has a hole for receiving guy lines.
U.S. Pat. No. 3,012,644 (Bush, 1961) describes an anchor pile that operates by means of a steel cable. The anchor pile comprises a hollow elongated body adapted to be driven into the ground, openings in the side of the elongated body, anchoring flukes pivotally connected to the body and adapted to spread outwardly, shoulders on the flukes, and means for collapsing the flukes against the side of the body. The means for collapsing the flukes extends through the openings in the side of the body and upwardly inside the hollow body.
U.S. Pat. No. 3,107,000 (Hynds, 1962) discloses another land anchor that requires an internal mechanism for its operation. The anchor comprises a shaft connected to a holding line at its upper end, a sleeve that surrounds the shaft and that can slide up and down on the shaft, and one or more flukes that are pivotally connected to the shaft. When the shaft is pulled upward, it causes the flukes to spread outward.
U.S. Pat. No. 3,279,136 (Smith, 1966) describes an umbrella pile anchor with flukes that open outward in a direction opposite that of the present invention. Specifically, the tips of the flukes move from bottom to top upon opening, rather than from top to bottom, as is the case with all of the other anchoring devices discussed herein. This particular anchor device was designed for use in a shipyard and cannot be installed on a fence post. As with U.S. Pat. No. 3,012,644 and U.S. Pat. No. 3,107,000, this anchor device requires an internal mechanism to open the flukes. In this case, the internal mechanism is an inner follower tube that sits inside of an outer follower tube.
U.S. Pat. No. 4,015,433 (Shibata, 1977) describes a method for settling an anchor device in the ground involving deep shafts that are bored into the ground. The method involves pulling a release line to rotate cutting arms that are attached to the shaft.
U.S. Pat. No. 4,738,060 (Marthaler et al., 1988) provides a marker assembly for permanently locating underground utility elements. The marker assembly includes a non-removable plastic stake and a flat marker that sits above ground. The underground part of the stake has a pair of flexible barbs that serve to grip the earth and hold the marker in position.
U.S. Pat. No. 4,738,063 (Alsop, 1988) discloses a ground anchoring system in which a generally flat anchor plate is secured to one end of a flexible anchor line and driven edge-first into the ground by a driving tool. According to the inventor, when the driving tool is removed and a lifting force is applied, the anchor plate tends to “skew” across the hole and resist extraction. This particular patent was intended to cover improvements devised by the inventor to prevent the anchor plate from rising back up the hole when the lifting force is applied. In U.S. Pat. No. 5,255,480 (Alsop, 1993), the inventor added a spring mechanism designed to force the anchor plates open.
U.S. Pat. No. 5,553,978 (Bates, 1996) provides a pivotable anchor for pilings. The anchor comprises a backing plate that is secured to the lower exterior portion of the piling, a pivot bracket that extends laterally out from the backing plate, a pivoting arm and a thrust plate.
U.S. Pat. No. 5,623,843 (Sands, 1997) relates to an anti-theft motorcycle tethering device that can be driven through asphalt, tarmac or pavement. The device consists of a solid metal stake with collapsible barbs that retract while the stake is being driven into the ground and deploy after the stake is in the ground. The upper end of the stake is adapted to permit a motorcycle to be tethered to it.
U.S. Pat. No. 6,474,028 (Cusimano et al., 2002) and U.S. Patent Application Pub. No. 2002/0088186 (Cusimano et al.) both involve a ground anchor designed to secure modular buildings exposed to earthquake, high winds and floods. The ground anchor comprises a heavy steel rod with several inches of machine threading and an arrowhead with a pair of wedge-shaped wings, a pivotal fluke that is hinged to the shaft with a lateral pin, a stabilizer vane that slips down over the threaded portion of the steel rod, and a cap that interlocks with the stabilizer vane.
Finally, U.S. Patent Application Pub. No. 2003/0221378 (Krieger) describes elongated tethering stakes with pivotally connected claws that extend outward when upward pressure is placed on the stakes. The stakes are connected at their impact end to a securing line. This particular invention was intended for use in securing animals or goods to a particular location.
As is clear from the above discussion, although the concept of using flanges or flukes to oppose the upward pressure of a rod or stake is known in the art, no one has ever patented a fence post anchor that is designed to work with modern metal fence posts, that requires no alteration of the existing fence post, that provides resistance on both sides of the fence post by virtue of two extending arms, and that is made from a single piece of material.